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B. J. PATTON FLUORESCENT TUBE REJUVENATOR Feb. 7, 1956 Filed Nov. 19, 1951 Fig.2

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"l: I4 l6 I8 20 Bernard J. Pa "on INVENTOR.

Attorneys United States Patent FLUORESCENT TUBE REJUVENATOR Bernard J. Patton, Los Angeles, Calif., assignor of fifteen per cent to Wallace Shaffer, Los Angeles, Calif.

Application November 19, 1951, Serial No. 257,051

7 Claims. (Cl. 316-28) This invention relates to a fluorescent tube rejuvenator and particularly to a device to restore to usefulness those fluorescent tubes which have become inoperative during use without the destruction of parts.

In the operation of fluorescent tubes it has been found that certain tubes become inoperative. Examination of these tubes shows that the parts are still intact and apparently in operative condition. However, for whatever reason the tubes have become inoperative, l have found that these tubes may be restored to activity or rejuvenated by the application at a high voltage with a predetermined load current.

' While the exact reason for the tubes becoming inoperative is not known, it is believed, that the tube either becomes inhibited because of some gas which has been adniitted from the electrodes, or, because the gases within the tube havemade inert compounds which are incapable of being activated by normal discharge in the tube. Also, it is possible that the tubes act as chemical combiners tocausecombination of gases in the tubes into poisonous compounds. I

It has also been supposed that the chemical activities within the tube. may cause a high resistance or substantially non-conducting shell on the electrodes so that all of the arc-drop is lost in the drop at the electrodes and not sufficient drop-is available to activate the gases in the tube.

Whatever the cause of the inactivity of the gases in the tube it is foundthat by applying a voltage between 5,000and 12,000 with a load current between 1 and 12 milliamperes the activity of the tube is restored.

. The present invention provides a rejuvenator for arranging the tubes to be rejuvenated and, for applying the proper potentials thereto.

It is accordingly an object of this invention to provide a fluorescent tube rejuvenator.

It is a-further objectof'this invention-to provide a rejuvenator for applying progressive load currents to progressive lengths of tubes.

1 It is a further object of this invention to provide a rejuvenator with means for selecting the tube current according to the wattage of the tube.

-It is a further object of this invention to provide a tuberejuvenator in which a load current through the tube can be selectively determined.

Other objects and many of the attendant advantages of this invention will be apparent from the following detailed description taken in conjunction with the accompanying drawing in which:

Figure 1 is a plan view of the rejuvenator; and

Figure 2 is a schematic wiring diagram of the rejuvenator.

According to the exemplary embodiment of the invention the rejuvenator includes a table or panel upon which is mounted a primary contact electrode 12 and a plurality of secondary electrodes 14, 16, 18 and 20, the secondary electrodes being spaced from the primary elec- '2 trodes according to the standard length of fluore' tubes of difierent wattages.

The distance between the primary electrode 12 and the first secondary electrode 14 is selected for the shortest of the fluorescent tubes and usually for the 15 watt tube. The secondary electrodes 14 to 20 inclusive are com nected in parallel by a bus connector 22. A primary bus connection 24 is also applied to the primary elec-' trode 12 and the buses 22 and 24 are arranged in paral lel relation.

Power is applied to the connection by means of a volt alternating current line 26 and energy is transferred from the line 26 to the buses 22 and 24 by means of a plurality of transformers 28, 30, 32, 34, 36, 38 and'40 inclusive. Transformers 28 to 40 are each, provided with switch control members in a primary connection, switches 29 to 41 inclusive being connected in series with the primary windings of the transformers 28 to'40iinelusive. The secondary terminals of the transformers'28 to 36 are connected in parallel to the buses 22 and 24 so that the voltage is substantially constant and the load current is dependent on the' number of transformers connected. The transformers 28 to 40 are of a type having secondary potential on the order of 5,000 to 12,000 volts usually the order of 7,500 and a secondary load current of the order of one milliampere per transformer. This is accomplished by utilizing a transformer with a high inductance ratio so that an increase in current will decrease the terminal voltage until the load current is substantially stabilized. v j

To rejuvenate a tube 42 it is placed across the appropriate terminals as the primaryterminal 12 and for a 15 watt tube secondaryterminal 14. .While the reason is not exactly known, it has been found, thatthe tubes require a load current substantially proportional to the wattage of the tube. It has further been found that the low wattage tubes on the order of 15 to 40 watts require a load current of the average of approximately one milliampere. Consequently, only one transformer-such as 28 is energizedby closing the switch 29 to supply the necessary load current at the order of 7,500 volts and the current of the order of one milliampere. This .load is applied for a time at the order of 15 seconds. If after the application of a rejuvenating current for 15 seconds there is no flicker or roll in the gas discharge inside the tube, the tube is restored and may be placed in the usual fixture.

Fluorescent discharge tubes of dilferent wattage-Will be placed between the appropriate secondary contact blocks 14 to 20 and the primary terminal 12 so that tubes being rejuvenated will extend. between the primary terminal 12 and the secondary terminals 16, 18 or 20 according to the standard length of the tube. Also-it has" been found that the load current must increase ap-- proximately with the increase in wattage of the tubes. For example, a 15 watt tube requires only a single transformer to supply the necessary load current. While tubes between 15 and 40 watts mayrequire eitherone or twotransformers to supply the necessary load as required by the tube. For each increase in standard wattage over the 40 watt tube it has been found that substantially two transformers must be cut in for each increase in wattage. While it is not exactly known what transpires in the tubes it is believed that the high voltage load current produces chemical reactions within the tubes or else it causes the acretions on the surface of the electrodes to be blasted away. It is strongly suspected that the presence of a high voltage discharge produces chemical combinations of gases which had intruded in the electrode and has seeped out to poison the gases causing the luminous display in the tube. The high voltage causes these gases latented Il'f'eb.

arsasra combine into inert material which is deposited either on the electrodes or on the sides of the tube to be in such position as to no longer interfere with the operation of the tube. Likewise, it is believed that any deposit on the exterior surface of the electrode will be blasted away and probably transferred to some inconspicuous place in thetube where it likewise will no longer affect the operation ofthe tube. However, irrespective of the reason for the rejuvenation it has been found that by applying the high potential loadcurrent discharge to the tubes fora period of approximately seconds many tubes are properly restored to useful life and when placed in the normal holders operate in the same manner as new tubes.

While for purposes of exemplification a particular embodiment of the invention has been shown, and described according to the best present understanding thereof, it will be apparent to those skilled in the art, that many changes and modifications may be applied therein without departing from the true spirit of the invention.

Having described the invention, what is claimed as new is:

l. A fluorescent tube rejuvenator comprising an elongated contact block, a plurality of elongated contact blocks arranged in progressively spaced relation to said first mentioned contact block, a conductor connecting said second mentioned blocks in parallel, a plurality of transformers, secondary terminals on each of said transformers, said secondary terminals being connected in parallel between said first block and said plurality of contact blocks, a supply circuit, primary terminals on each of said transformers, switch means operative to selectively connect said primary terminals in parallel to said supply circuit.

2. A fluorescenttube rejuvenator comprising an elongated contact block, a plurality of elongated contact blocks arranged in progressively spaced relation to said first mentioned contact block, a conductor connecting said second mentioned blocks in parallel, a plurality of transformers, secondary terminals on each of said transformers, said secondary terminals being connected in parallel between said first block and said plurality of contact blocks, aseparate switch for each of said transformers, a supply circuit, said switches being operative to selectively connected said transformers in parallel to said supply circuit each of said transformers having a terminal voltage of the order of 7500 volts and a load current of the order of one milliampere.

3. A fluorescent tube rejuvenator comprising an elongated contact block, a plurality of secondary contact blocks, said secondary contact blocks being progressively spaced from said first mentioned contact block according to the progressive length of fluorescent tubes of progressively increased wattage, a conductor connecting said secondary blocks in parallel, a plurality of transformers each having primary and secondary terminals, said secondary terminals being connected in parallel between said first mentioned contact block and said secondary blocks, said transformers having high impedance to limit the load current delivered thereby an independent switch for each of said transformers, a supply circuit, said switches being operative to selectively connect said primary terminals in parallel to said supply circuit.

4,- A fluorescent tube rejuvenator comprising an elongated contact block, a plurality of secondary contact blocks, said secondary contact blocks being progressively spaced from said first mentioned contact block according to the progressive length of fluorescent tubes of progressively increasing wattage, a conductor connecting said secondary blocks in parallel, a plurality of transformers each having primary and secondary terminals, said secondary terminals being connected in parallel between said first contact block and said secondary contact blocks, said transformers having a high impedence to limit the load current of the individual transformers and an independent switch for each of said transformers, a supply circuit, said switches being operative to selectively connect said primary terminals to said supply circuit to select the total load current.

5. A fluorescent tube rejuvenator comprising an elongated contact block, a plurality of elongated contact blocks arranged in progressively spaced relation to said first mentioned contact block, whereby fluorescent tubes of diiferent wattages may be positioned between said blocks, a conductor connecting said second mentioned blocks in parallel, a plurality of transformers connected in parallel between said first block and said second block, and a separate switch for energizing each of said transformers in parallel from a common supply circuit.

6. A fluorescent tube rejuvenator comprising an elongated contact block, a plurality of contact blocks arranged at progressively spaced distances from said first mentioned contact block and also staggered with respect thereto, whereby a fluorescent tube of any standard length may be positioned between said first mentioned contact block and one of said second mentioned contact blocks, a comv ductor connecting said second mentioned blocks in paral lel, a plurality of transformers connected in parallel between said first block and said second blocks, a switch for each of said transformers, to' selectively determine the total load current applied to the tubes positioned between said blocks.

7. A fluorescent tube rejuvenator comprising a first and second contact block, each contact block being adapted to make electrical contact with the terminals at the end of a fluorescent tube, said contact blocks being spaced apart a distance to receive a fluorescent tube therebetween with the respective end terminals in contact with the respective contact blocks, a plurality of high inductance transformers having primary and secondary terminals, said secondary terminals being permanently connected in parallel, one of said parallel terminals being connected to the first contact block the other terminals being con nected to the second contact block, a primary supply circuit, switch means operable to selectively connect the primary terminals of said transformers to said supply circuit, said primary terminals when connected to said supply circuit being in parallel circuit relationi Skinker Aug. 26, 1947 

